DevOps Classroom Series – 21/Feb/2021 (Evg)

Git Hooks

• Git Hooks are scripts that run automatically every time a particular event occurs in Git Repository
• Git Hooks are located in the .git/hooks
• Git Hooks call the scripts which can be in any scripting language
• Git Hooks are of two types
  • Client Side Hooks:
    • These are executed on the commiter’s system
    • This can be further categorized as
      • Commiting workflow hooks
      • Email Workflow Hooks
      • Other
  • Server-Side Hooks: These are executed on the remote repository. These are divided into following categories.
    • Pre-receive and Post-receive hooks
    • Update
  • Server Side Hooks are the scripts which are executed on server, but if the organization is using cloud/hosted repositories like GitHub/Code Commit/ Azure Source Repos/Bit Bucket then web hooks are enabled.
• Some of the popular hooks
  • applypatch-msg: Invoked by git am
  • pre-applypatch:
  • post-applypatch:
  • pre-commit: executed by git commit
  • prepare-commit-msg: executed by git commit
  • commit-msg: executed by git commit
  • post-commit: executed by git commit
  • pre-rebase
  • post-checkout: git checkout and git clone
  • post-merge: git merge and git pull
  • pre-push
  • pre-recieve
  • update
  • post-recieve
  • post-update
• Sample pre-commit hook

#!/bin/bash
echo " precommit"
set

• With hooks whenever developer submits code we can execute functionality by calling hook scripts, So when developer submits code we can call
  • Jenkins to build
  • Ansible to deploy
  • Terraform to deploy
• If you do these kind of activities where your pipeline is triggered as part of git hook it is also referred as git ops.
• In the case of git hub we can configure web hooks and from there call the pipeline

Git Branching Strategy

• Refer Here
• Per project:
  • Day builds: multiple times a day
    • Build the code, package the code, run unit tests, run sonar qube
  • Night builds: execute once in day:
    • Build the code, package the code, upload the package to artifactory
    • Run unit tests
    • Create test environments (run configuration management/infraprovisioning)
    • Run QA tests (Selenium/QTP)
    • Run Perf tests (Jmeter/Loadrunner)
  • Production builds: execute once per release